util: move all to shared/ and split external dependencies in separate internal libraries

Before:
  $ ldd /lib/systemd/systemd-timestamp
  linux-vdso.so.1 =>  (0x00007fffb05ff000)
  libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f90aac57000)
  libcap.so.2 => /lib64/libcap.so.2 (0x00007f90aaa53000)
  librt.so.1 => /lib64/librt.so.1 (0x00007f90aa84a000)
  libc.so.6 => /lib64/libc.so.6 (0x00007f90aa494000)
  /lib64/ld-linux-x86-64.so.2 (0x00007f90aae90000)
  libdl.so.2 => /lib64/libdl.so.2 (0x00007f90aa290000)
  libattr.so.1 => /lib64/libattr.so.1 (0x00007f90aa08a000)
  libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f90a9e6e000)

After:
  $ ldd systemd-timestamp
  linux-vdso.so.1 =>  (0x00007fff3cbff000)
  libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f5eaa1c3000)
  librt.so.1 => /lib64/librt.so.1 (0x00007f5ea9fbb000)
  libc.so.6 => /lib64/libc.so.6 (0x00007f5ea9c04000)
  /lib64/ld-linux-x86-64.so.2 (0x00007f5eaa3fc000)
  libdl.so.2 => /lib64/libdl.so.2 (0x00007f5ea9a00000)
  libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f5ea97e4000)

1 files changed, 102 insertions, 0 deletions

diff --git a/src/shared/socket-util.h b/src/shared/socket-util.h
new file mode 100644
index 0000000000..8ccbd371cf
--- /dev/null
+++ b/src/shared/socket-util.h
@@ -0,0 +1,102 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosocketutilhfoo
+#define foosocketutilhfoo
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <sys/un.h>
+#include <net/if.h>
+#include <asm/types.h>
+#include <linux/netlink.h>
+
+#include "macro.h"
+#include "util.h"
+
+union sockaddr_union {
+        struct sockaddr sa;
+        struct sockaddr_in in4;
+        struct sockaddr_in6 in6;
+        struct sockaddr_un un;
+        struct sockaddr_nl nl;
+        struct sockaddr_storage storage;
+};
+
+typedef struct SocketAddress {
+        union sockaddr_union sockaddr;
+
+        /* We store the size here explicitly due to the weird
+         * sockaddr_un semantics for abstract sockets */
+        socklen_t size;
+
+        /* Socket type, i.e. SOCK_STREAM, SOCK_DGRAM, ... */
+        int type;
+
+        /* Socket protocol, IPPROTO_xxx, usually 0, except for netlink */
+        int protocol;
+} SocketAddress;
+
+typedef enum SocketAddressBindIPv6Only {
+        SOCKET_ADDRESS_DEFAULT,
+        SOCKET_ADDRESS_BOTH,
+        SOCKET_ADDRESS_IPV6_ONLY,
+        _SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX,
+        _SOCKET_ADDRESS_BIND_IPV6_ONLY_INVALID = -1
+} SocketAddressBindIPv6Only;
+
+#define socket_address_family(a) ((a)->sockaddr.sa.sa_family)
+
+int socket_address_parse(SocketAddress *a, const char *s);
+int socket_address_parse_netlink(SocketAddress *a, const char *s);
+int socket_address_print(const SocketAddress *a, char **p);
+int socket_address_verify(const SocketAddress *a);
+
+bool socket_address_can_accept(const SocketAddress *a);
+
+int socket_address_listen(
+                const SocketAddress *a,
+                int backlog,
+                SocketAddressBindIPv6Only only,
+                const char *bind_to_device,
+                bool free_bind,
+                bool transparent,
+                mode_t directory_mode,
+                mode_t socket_mode,
+                const char *label,
+                int *ret);
+
+bool socket_address_is(const SocketAddress *a, const char *s, int type);
+bool socket_address_is_netlink(const SocketAddress *a, const char *s);
+
+bool socket_address_equal(const SocketAddress *a, const SocketAddress *b);
+
+bool socket_address_needs_mount(const SocketAddress *a, const char *prefix);
+
+const char* socket_address_bind_ipv6_only_to_string(SocketAddressBindIPv6Only b);
+SocketAddressBindIPv6Only socket_address_bind_ipv6_only_from_string(const char *s);
+
+const char* netlink_family_to_string(int b);
+int netlink_family_from_string(const char *s);
+
+bool socket_ipv6_is_supported(void);
+
+#endif